Javier A. Ruiz

University of Chile · Departamento de Geofísica

Large subduction earthquakes induce complex postseismic deformation, primarily driven by afterslip and viscoelastic relaxation, in addition to interplate relocking processes. However, these signals are intricately intertwined, posing challenges in determining the timing and nature of relocking. Here, we use six years of continuous GNSS measurements...

Large subduction earthquakes induce complex postseismic deformation, primarily driven by afterslip and viscoelastic relaxation, in addition to interplate relocking processes. However, these signals are intricately intertwined, posing challenges in determining the timing and nature of relocking. Here, we use six years of continuous GNSS measurements...

Geodetically constrained interseismic interplate coupling has been widely used to assess seismic potential in subduction zones. Modeling interseismic deformation is challenging, as it involves interplate coupling and often ignores continental internal deformation processes. We present a novel methodology to jointly estimate interplate coupling alon...

Dehydration of the oceanic subducting slab promotes the formation of magmatic arcs, intra-slab intermediate-depth seismicity, and hydration of the overlying mantle wedge. However, the complex permeability structure of the overriding plate controls the magma and fluid migration and their accumulation at shallower depths. In this regard, mapping the...

Imaging subsurface fault slip from surface observations is essential to improving our understanding of the physics of earthquakes and tsunamis. As the estimation of subsurface fault slip is inherently ill-posed, common inversion methods usually require a regularization term to counteract instabilities. Such regularization introduces biases in infer...

The third sentence in the Acknowledgments section, “Support for J. Mieres Madrid to visit OSU and SIO was provided by CONICYT/FONDECYT grant 11170047(Un. Chile; J. Ruiz and E. Contreras-Reyes),” should be replaced by the three sentences below. Support for JMM to visit OSU and SIO was provided by grant CHILE-USA2002 (CONICYT), to E. Contreras-Reyes...

To investigate the dynamic response of the outer accretionary prism updip from the patch of greatest slip during the 2010 Mw 8.8 Maule earthquake (Chile), 10 ocean-bottom seismometers (OBSs) were deployed from May 2012 to March 2013 in a small network with an inter-instrument spacing of 7–10 km. Nine were recovered, with four recording data from in...

We study the structure and tectonics of the collision zone between the Nazca Ridge (NR) and the Peruvian margin constrained by seismic, gravimetric, bathymetric, and natural seismological data. The NR was formed in an on‐ridge setting, and it is characterized by a smooth and broad shallow seafloor (swell) with an estimated buoyancy flux of ~7 Mg/s....

The March 16, 2014 Mw 6.7 earthquake played an important role in the complex seismic sequence leading to the nucleation of the April 1st, 2014 Mw 8.2 Pisagua earthquake in northern Chile. The Mw 6.7, an upper plate reverse faulting event with nodal planes highly rotated counterclockwise with respect to the strike of the megathrust at its location,...

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Recent studies have proposed that nucleation zones, seismic barriers and high-slip patches of megathrust earthquakes correlate with physical heterogeneities, both in the oceanic/subducting plate and in the continental wedge. We present a density-depth model along the Nazca-South America subduction margin, from 18°S to 23°30'S, where a partial segme...

We study the rupture processes of Iquique earthquake M w 8.1 (2014/04/01) and its largest aftershock M w 7.7 (2014/04/03) that ruptured the North Chile subduction zone. High-rate Global Positioning System (GPS) recordings and strong motion data are used to reconstruct the evolution of the slip amplitude, rise time and rupture time of both earthquak...

On 25 December 2016, a Mw 7.6 earthquake broke a portion of the Southern Chilean subduction zone south of Chiloé Island, located in the central part of the Mw 9.5 1960 Valdivia earthquake. This region is characterized by repeated earthquakes in 1960 and historical times with very sparse interseismic activity due to the subduction of a young (~15 Ma...

The time characteristics of the seismic source are usually neglected in tsunami modeling, due to the difference in the time scale of both processes. Nonetheless, there are just a few analytical studies that intended to explain separately the role of the rise time and the rupture velocity. In this work, we extend an analytical 1 + 1 D solution for t...

The central Chilean margin (32°–33°S) is characterized by the subduction of the Juan Fernández Ridge (JFR) beneath the continental South American plate. The JFR corresponds to a hotspot track composed by seamounts typically 3–3.5km high above the surrounding seafloor, with a ridge-trench collision zone underlying the prominent Valparaiso Forearc Ba...

The Mw 8.8 megathrust earthquake that occurred on 27 February 2010 offshore the Maule region of central Chile triggered a destructive tsunami. Whether the earthquake rupture extended to the shallow part of the plate boundary near the trench remains controversial. The up-dip limit of rupture during large subduction zone earthquakes has important imp...

The pre- and current collision of the Juan Fernández Ridge with the central Chilean margin at 31°–33°S is characterized by large-scale crustal thinning and long-term subsidence of the submarine forearc caused by subduction erosion processes. Here, we study the structure of the central Chilean margin in the ridge–trench collision zone by using wide-...

A large seismic gap lies along northern Chile and could potentially trigger a M w ~ 8.8–9.0 megathrust earthquake as pointed out in several studies. The April 1, 2014, Pisagua earthquake broke the middle segment of the megathrust. Some slip models suggest that it ruptured mainly from a depth of 30 to 55 km along dip and over 180 km in length, reach...

A general method of solution for the runup evolution and some analytical results concerning a more general bathymetry than a canonical sloping beach model are presented. We studied theoretically the water wave elevation and runup generated on a continuous piecewise linear bathymetry, by solving analytically the linear shallow water wave equations i...

The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. The moment magnitude (Mw) 8.1 Iquique earthquake of 1 April 2014 broke a highly coupled portion of this gap. To understand the seismicity preceding this event, we studied the location and mechanisms of the foreshocks and computed Global Positioning Sy...

On 2010 March 11, a sequence of large, shallow continental crust earthquakes shook central Chile. Two normal faulting events with magnitudes around M_w 7.0 and M_w 6.9 occurred just 15 min apart, located near the town of Pichilemu. These kinds of large intraplate, inland crustal earthquakes are rare above the Chilean subduction zone, and it is impo...

On 2010 March 11, a sequence of large, shallow continental crust earthquakes shook central Chile. Two normal faulting events with magnitudes around Mw 7.0 and Mw 6.9 occurred just 15 min apart, located near the town of Pichilemu. These kinds of large intraplate, inland crustal earthquakes are rare above the Chilean subduction zone, and it is import...

We present a theoretical solution for the water wave elevation along the shoreline and a closed formula is derived for the runup distribution in the 2+1 dimensional (2 spatial + 1 temporal) linear case. An integral transform method is used to solve the linear shallow water wave equations for a sloping beach model extended along the coastline. At la...

A hybrid empirical method is proposed to simulate broadband strong ground motion that combines a kinematic complex source model with both Numerical and Empirical Green's Functions (EGF). The kinematic approach is based on a composite source model description where subevents are generated using a fractal distribution of sizes. Each subevent is set u...

The San Ramón Fault is an active west-vergent thrust fault system located along the eastern border of the city of Santiago, at the foot of the main Andes Cordillera. This is a kilometric crustal-scale structure recently recognized that represents a potential source for geological hazards. In this work, we provide new seismological evidences and str...

The kinematic fractal source model presented in this study is able to simulate broad-band accelerograms with spectral amplitudes proportional to a fraction of the directivity coefficient Cd in the far-field approximation. This approach is based on a composite source description, where subevents are generated using a fractal distribution of sizes, a...

The Mw=8.8 Maule earthquake off the coast of Chile on February 27, 2010 is the 5th largest megathrust earthquake ever to be recorded and the 2nd largest to be recorded by modern digital seismic networks. Immediately following the Maule earthquake, teams of seismologists from Germany, France, the UK, and the US, working with seismologists in Chile,...

During the last decade, efforts to improve our knowledge of great Chilean earthquakes have shown that not all of the major destructive events have occurred in the contact between the Nazca and south American plates (interplate earthquakes). Waveform analysis of records from the Ms = 8.0, 1950 Antofagasta and the Ms = 7.8, 1939 Chillán earthquakes h...

In an attempt to improve the ground motion modelling, the characteristics of the slip velocity functions (SVF) generated using the kinematic k−2 source are investigated and compared to the dynamic solutions proposed in the literature. Several numerical simulations were performed to test the influence of the model parameters on the SVF modelling. Ov...

We show source characteristics of the 2005 Tarapaca earthquake that occurred at a depth around 115 km (NEIC) in the east-dipping Wadati-Benioff zone beneath northern Chile. Accelerograms of the mainshock were successfully recorded by five strong-motion stations of Universidad de Chile within 300 km of the epicentral distance. We analyzed the data u...